The invention relates to a belt spool for a belt retractor, comprising a torsion rod and a spool body that has a recess in which is provided a shaped part by means of which an end of a safety belt can be fastened in the recess. The invention also relates to a belt retractor comprising such a belt spool.
DE 296 05 115 discloses such a belt spool in which the shaped part is supported on the recess in the body of the belt spool Therefore, the spool body of the belt spool has to be stable enough to be able to absorb the tensile load of the safety belt.
It is the object of the invention to provide a simple and lightweight belt spool.
According to the invention, a belt spool for a belt retractor comprises a torsion rod and a spool body that has a recess in which is provided a shaped part by means of which an end of a safety belt can be fastened in the recess. The shaped part rests at the torsion rod in order to be supported when the shaped part is stressed by a tensile load of the safety belt. In this manner, the torsion rod can absorb the tensile load of the safety belt. However, the spool body of the belt spool no longer has to be as stable as a spool body that has to withstand the entire tensile load of the safety belt. This results in considerable weight savings since, first of all, a lighter material can be used for the spool body and secondly, a smaller diameter can be selected for the spool body
According to a preferred embodiment, the torsion rod has two hub sections with which it engages the spool body, and an axle section that connects the two hub sections to each other, the shaped part being only supported on the torsion rod at the hub sections. In this manner, the tensile load of the safety belt is only applied to the torsion rod at the hub sections, so that the torsion rod is prevented from bending, which would impair the primary function of the torsion rod, namely, to delimit the belt force. Via the hub sections, however, the torsion rod can transfer the load to the belt spool with a relatively short path, and from here, the force is absorbed by the bearings of the housing of the belt retractor.
Moreover, the invention proposes a belt retractor comprising a safety belt and an above-mentioned belt spool, an end of the safety belt forming a loop that surrounds the shaped part. Such a belt retractor can be made smaller since the space requirement for the wound-up belt is reduced in the case of a belt spool the spool body of which has a smaller diameter.
Additional advantageous embodiments of the invention will be apparent from the subordinate claims.